I got my special edition Beyerdynamic DT990/600 Ohm two weeks ago and became a fan of Tidal HIFI ever since. I have never been an 'avid' music listener but I am getting there because of these two. My iPhone drives the HPs ok but I could use an amp at my workplace. At home, my Denon AVR-S510BT does a good job with music, movies etc. I need a compact portable tube-based amp (I read reviews that tube amps really bring the good sound out compared to SS) at my workplace that is not too huge. I have also read that tube preamp+SS amp combo is considered better sometimes. My budge is around $150. My source is Tidal HIFI on my iPhone 8. I am already looking at Tube Amp: Nobsound 6N3 -> http://www.doukaudio.com/nobsound-6...r-stereo-earphone-amp-hi-fi-preamp_p0064.html and tube preamp: http://www.doukaudio.com/nobsound-n...-audio-pre-amplifier-trebleampbass_p0016.html I thought it would be best to ask you guys for expert advice on my first tube amp or tube-preamp+SS amp combo. Thanks in advance.